Commit bab0c318 authored by Paolo Bonzini's avatar Paolo Bonzini
Browse files

KVM: x86: do not reset microcode version on INIT or RESET 



Do not initialize the microcode version at RESET or INIT, only on vCPU
creation.   Microcode updates are not lost during INIT, and exact
behavior across a warm RESET is not specified by the architecture.

Since we do not support a microcode update directly from the hypervisor,
but only as a result of userspace setting the microcode version MSR,
it's simpler for userspace if we do nothing in KVM and let userspace
emulate behavior for RESET as it sees fit.

Userspace can tie the fix to the availability of MSR_IA32_UCODE_REV in
the list of emulated MSRs.

Reported-by: default avatarAlex Williamson <alex.williamson@redhat.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent bb6d3fb3

arch/x86/kvm/svm.c

+1 −1
Original line number Diff line number Diff line
@@ -2175,7 +2175,6 @@ static void svm_vcpu_reset(struct kvm_vcpu *vcpu, bool init_event) 
	u32 dummy;

	u32 eax = 1;



	vcpu->arch.microcode_version = 0x01000065;

	svm->spec_ctrl = 0;

	svm->virt_spec_ctrl = 0;
@@ -2266,6 +2265,7 @@ static int svm_create_vcpu(struct kvm_vcpu *vcpu) 
	init_vmcb(svm);



	svm_init_osvw(vcpu);

	vcpu->arch.microcode_version = 0x01000065;



	return 0;

arch/x86/kvm/vmx/vmx.c

+1 −1
Original line number Diff line number Diff line
@@ -4238,7 +4238,6 @@ static void vmx_vcpu_reset(struct kvm_vcpu *vcpu, bool init_event) 


	vmx->msr_ia32_umwait_control = 0;



	vcpu->arch.microcode_version = 0x100000000ULL;

	vmx->vcpu.arch.regs[VCPU_REGS_RDX] = get_rdx_init_val();

	vmx->hv_deadline_tsc = -1;

	kvm_set_cr8(vcpu, 0);
@@ -6763,6 +6762,7 @@ static int vmx_create_vcpu(struct kvm_vcpu *vcpu) 
	vmx->nested.posted_intr_nv = -1;

	vmx->nested.current_vmptr = -1ull;



	vcpu->arch.microcode_version = 0x100000000ULL;

	vmx->msr_ia32_feature_control_valid_bits = FEAT_CTL_LOCKED;



	/*